JP2002264825A - Intermediate shaft for steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a current intermediate shaft for a steering device that a cylinder and a shaft extendably fitted to each other are hard to be drawn due to a dead weight thereof and hard to be assembled in a vehicle. SOLUTION: In the intermediate shaft 1 of this steering device, the cylinder 4 and the shaft 5 are extendably fitted to each other, and the end of the cylinder 4 is provided with a seal member 6 for sealing the peripheral surface of the shaft 5, while allowing the sliding of the shaft 5. The shaft 5 is formed of an engagement projection 55 to be engaged with the seal member 6. This engagement projection 55 is engaged with the seal member 6 in an only predetermined shrunken condition that is an attitude in assembling, and the engagement projection 55 can maintain the intermediate shaft 1 in an assembling attitude, restricting the dead weight of the cylinder 4, to facilitate the assembling. The intermediate shaft 1 can be smoothly extended and shrunken by releasing an engagement. The engagement projection 55 can be formed at a low cost by utilizing the thick part 58 of a resin coated part 54 for reducing sliding resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an intermediate shaft of a steering device for an automobile or the like.

[0002]

2. Description of the Related Art For example, a steering device that transmits the movement of a steering wheel to wheels via a steering shaft, an intermediate shaft, and a steering gear including a rack-and-pinion mechanism to steer the wheels. is there. The above-mentioned intermediate shaft is usually made expandable and contractable, and is constituted by a shaft and a cylinder fitted to each other. The outer peripheral surface of the shaft consists of a smooth surface extending parallel to the axial direction,
A seal member that slides on the outer peripheral surface of the shaft is attached to a fitting portion between the shaft and the cylinder. The intermediate shaft can be expanded and contracted with a light force in the entire range of expansion and contraction.

[0003]

However, in such an intermediate shaft, there is a risk that, for example, a lower cylinder may come off due to its own weight when incorporated into a vehicle. That is, when assembling the intermediate shaft to the vehicle, first, the upper shaft is attached to the vehicle side in a state where the intermediate shaft is shortened, but at this time, the tube is manually held so that the lower tube does not come off. You need to keep it. As a result, the shaft is attached while holding the cylinder, which is difficult to assemble.

It is conceivable to increase the sliding resistance at the time of expansion and contraction in order to prevent withdrawal, but it is not preferable because the operating resistance is increased by the normal expansion and contraction operation after assembly. Therefore, an object of the present invention is to solve the above-described technical problems and to provide an intermediate shaft of a steering device that can be easily incorporated into an actual machine and does not hinder the operation after the assembly.

[0005]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 comprises a cylinder and a shaft which are fitted to each other so as to be extendable and contractable, and a pull-out load due to its own weight when incorporated into an actual machine in a substantially shortened state. In the intermediate shaft of the steering device, the seal member is provided at the end of the cylinder to allow the shaft to slide, and the seal member is provided on the shaft and engages with the seal member only in the above-described substantially shortened state to reduce the above-mentioned load. An intermediate projection of the steering device, further comprising an engagement projection for generating an engaging engagement force.

According to the present invention, the posture of the vehicle when assembled into the vehicle can be maintained autonomously, so that the intermediate shaft does not have to be supported by the hand during assembly, resulting in easy work. Further, by applying a force exceeding the above-described engagement force, the seal member can be moved over the engagement protrusion. In a state in which the engagement protrusion is released by slightly extending the state from the substantially shortened state and disengaging the engagement projection, the expansion and contraction can be performed smoothly, so that the normal operation after assembly can be substantially prevented.

According to a second aspect of the present invention, in the intermediate shaft of the first aspect, the engagement projection has an engagement slope on a side where the shaft is removed, and is engaged in the substantially shortest state. The projection is provided in the cylinder, and the engagement slope is engaged with the inner peripheral edge of the seal member. According to the present invention, since the seal member is hooked and engaged with the engagement slope, the engagement force can be increased. Note that the slope may have an angle sufficient to prevent damage to the seal member.

According to a third aspect of the present invention, in the intermediate shaft of the steering device according to the first or second aspect, the engagement protrusion is formed by thickening a part of a resin coating portion coated on an outer peripheral surface of the shaft. An intermediate shaft of a steering device characterized by being formed as follows. According to the present invention, usually, only a part of the resin coating portion formed on the shaft needs to be thickened, so that the engagement protrusion can be easily formed, and the manufacturing cost can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An intermediate shaft of a steering device according to one embodiment of the present invention will be described below. FIG. 1 is a schematic diagram illustrating a state in which the above-described intermediate shaft is assembled to a vehicle. FIG. 2 is a front view of a main part of the above-described intermediate shaft. The intermediate shaft 1 is configured to be able to expand and contract in its axial direction (see arrow S). A universal joint 11 is provided at one end 2 of the intermediate shaft 1. One end 2 is integrally rotatably connected to a steering wheel 16 via a universal joint 11 and a steering shaft 15 connected thereto. Also,
A universal joint 12 is provided at the other end 3 of the intermediate shaft 1.
The other end 3 is not shown via a universal joint 12,
The input shaft of the steering gear for wheel steering is integrally rotatably connected. The steering gear has a pinion that rotates integrally with the input shaft, and a rack shaft that meshes with the pinion. The rack shaft slides in the left-right direction of the vehicle as the pinion rotates. When the steering wheel 16 is turned, the rotation is transmitted to the pinion via the steering shaft 15, the intermediate shaft 1, and the input shaft of the steering gear. Accordingly, the rack shaft moves, and the wheels are steered.

The intermediate shaft 1 is configured to be expandable and contractable in order to absorb the impact from the wheels and to make it easy to assemble the vehicle 17 (only a part is shown). That is, the intermediate shaft 1 is provided with a cylinder 4 which is fitted to be stretchable in the axial direction.
And a shaft 5. The cylinder 4 and the shaft 5 are formed of a hard member such as a metal, and are arranged concentrically. The fitting portion 50 of the shaft 5 can rotate integrally with the fitting portion 40 of the cylinder 4 and slide in the axial direction. It is fitted as possible. The shaft 5 extends from the end 41 of the cylinder 4, and the end 41 is provided with an annular seal member 6 for preventing foreign matter such as water and dust from entering the inside 43 of the cylinder 4. ing.

The fitting portion 40 of the cylinder 4 is provided near the end 41. As shown in the sectional view of FIG.
Has an internal gear shape, and has a plurality of, for example, four concave ridges 44. These concave stripes 44 extend at a predetermined length in the axial direction and are evenly arranged in the circumferential direction. The fitting portion 50 of the shaft 5 is configured as a spline shaft composed of a hollow shaft having an irregular cross section of an external gear shape. The fitting portion 50 includes a plurality of, for example, four ridges 51.
Having. These ridges 51 extend in the axial direction over substantially the entire length of the shaft 5, and are evenly arranged in the circumferential direction corresponding to the concave ridges 44. Even when the shaft 5 and the cylinder 4 are relatively moved in the axial direction, at least a part of the ridge 51 and the concave ridge 44 are engaged with each other, and the relative rotation between the shaft 5 and the cylinder 4 is restricted.

The outer peripheral surface 59 of the shaft 5 is
1 and a plurality of hollow peripheral surfaces 53 formed of cylindrical surfaces formed between the adjacent ridges 51.
These peripheral surfaces 53 are formed on the inner peripheral surface 46 of the cylinder 4 facing the peripheral surface 53.
There is a gap between them. Further, the tip surface 6 of the ridge 51
A gap is provided between the inner peripheral surface 46 of the cylinder 4 and the inner peripheral surface 46 of the cylinder 4 facing the inner peripheral surface 46. The outer peripheral surface 59 has a resin coating portion 54 made of a synthetic resin for reducing sliding resistance in almost the entire axial and circumferential directions. In addition, the resin coating 5
The outer peripheral surface 59 formed by 4 is in contact with the seal member 6 all around in the circumferential direction.

The seal member 6 is formed of an elastic material such as synthetic rubber or natural rubber, and is fixed to the outer peripheral surface of the cylinder 4 in a press-fit state. The inner peripheral edge portion 31 of the seal member 6 is formed to have substantially the same cross-sectional shape as the shaft 5, and allows the shaft 5 to slide while sealing between the inner peripheral edge portion 31 and the outer peripheral surface 59 of the shaft 5. During normal operation,
The inner peripheral edge 31 of the seal member 6 is in sliding contact with the axially intermediate portion of the outer peripheral surface 59 of the shaft 5, so that the sliding resistance between the seal member 6 and the shaft 5 is reduced.

By the way, such an extendable intermediate shaft 1
In this case, as shown in FIG. 1, the vehicle is usually incorporated into a vehicle as a real machine in a predetermined shortened state. The contracted intermediate shaft 1 tends to expand by its own weight when assembled. For example, when the shaft 5 is disposed on the upper side and the shaft 5 is assembled to the vehicle first, the cylinder 4 disposed on the lower side receives a detachment load (see arrow F) due to its own weight, and the shaft 5
, The cylinder 4 tends to come out downward. In the present invention, it is possible to prevent the cylinder 4 from coming off and obtain the intermediate shaft 1 that is easy to assemble as described below.

As shown in FIG. 4, the shaft 5 of the intermediate shaft 1 according to the present invention is provided with an engagement projection 55 which engages with the seal member 6 only in a predetermined shortened state. The engagement protrusion 55 is engaged with the seal member 6 to generate an engagement force against a detachment load. Here, the detachment load may be a detachment load corresponding to the own weight of the cylinder 4 when the cylinder 4 comes off as described above, or conversely, the shaft 5 when the shaft 5 comes off from the cylinder 4
The load may be a pull-out load corresponding to the own weight. Hereinafter, the former load will be described as an example.

The above-mentioned predetermined shortened state is a state close to the most shortened state in which the tip of the shaft 5 is pushed most into the inner part of the cylinder 4, and the state in which the intermediate shaft 1 is extended by a predetermined amount from the most shortened state. . In addition, the predetermined shortened state is a state in which power is transmitted and the state is contracted more than a normal operation state in which the vehicle is telescopically assembled. Note that the predetermined shortened state may be the shortest state, or may be any state that is substantially the shortest state. here,
The substantially shortest state is a concept including a shortest state and a state in which the intermediate shaft 1 is extended by a predetermined amount from the shortest state.

The engagement projection 55 is provided in the vicinity of the end of the shaft 5 and, in the above-described predetermined shortened state, the inner peripheral edge 3 of the seal member 6.
It is provided in the vicinity of the portion of the shaft 5 opposed to 1, and is disposed at a position to be the inside 43 of the cylinder 4. Also, the engagement protrusion 55
Is disposed on the side where the shaft 5 comes off from this part, avoiding the part of the shaft 5 that slides on the inner peripheral edge 31 of the seal member 6 during normal operation. In the predetermined shortened state, a space for the seal member 6 is secured adjacent to the engagement protrusion 55 in the axial direction. This space is around a shaft 5 opposite the tube 4. The engagement projection 55 is disposed outside the cylinder 4 during normal operation, that is, when the intermediate shaft 1 expands and contracts in a state after assembly, so that the engagement projection 55 does not contact the inner surface of the cylinder 4 and the seal member 6. I have.

In the engaged state, the inner peripheral edge 3 of the seal member 6
An elastic restoring force acting as a deformation resistance and a friction force acting as a sliding resistance act between the engagement projection 55 and the engagement projection 55.
The engagement force which maintains the engagement with the inner peripheral edge portion 31 of the seal member 6 is obtained. This engagement force is larger than the sliding resistance during normal operation, and has a size that can support the weight of the cylinder 4. Even if a load is applied to the cylinder 4 when assembled,
The above-mentioned engaging force against the disengagement load makes it possible to autonomously maintain the predetermined shortened state that is the posture at the time of assembling into the vehicle, so that the intermediate shaft 1 does not need to be supported by the hand at the time of assembling. .

The engagement between the engagement projection 55 and the seal member 6 is set to a degree that can be released by manual operation.
Therefore, if a force exceeding the engagement force is applied between the cylinder 4 and the shaft 5 so as to extend the intermediate shaft 1, the seal member 6 can get over the engagement protrusion 55. Then, in a state where the engagement of the engagement protrusion 55 is released by slightly extending the predetermined shortened state, the intermediate shaft 1 can be smoothly expanded and contracted. In particular, the engaging projection 55 does not engage with the cylinder 4 and the seal member 6 during the normal operation after assembly, so that the normal operation is not hindered.

The engagement projection 55 has an engagement slope 56 on the side from which the shaft 5 comes off. The engagement protrusion 55 is located in the inside 43 of the cylinder 4 in a predetermined shortened state, and engages the engagement slope 56 with the inner peripheral edge 31 of the seal member 6. In the predetermined shortened state, the sealing member 6 is hooked and engaged with the engagement slope 56, so that the engagement force can be increased. Also,
The engagement protrusion 55 has a substantially trapezoidal cross section including the axial direction, and has an introduction slope 57 on the pushing side of the shaft 5. The introduction slope 57 and the engagement slope 56 are formed obliquely with respect to the axial direction, and the inclination angle is an angle sufficient to prevent damage to the seal member 6.

The engaging projection 55 is formed by a thick portion 58 formed by thickening a part of the resin coating portion 54 of the shaft 5. The resin coating portion 54 covers the metallic main portion of the shaft 5 and
Are formed on the outer peripheral surface 59. The resin coating portion 54 is made of a polyamide resin, and has a fitting portion 40, 50 between the cylinder 4 and the shaft 5.
Reduce the sliding resistance between each other. When viewed in a cross section including the axial direction, adjacent portions of the resin coating portion 54 on both sides in the axial direction with respect to the thick portion 58 are relatively thin, and the thick portion 58 It protrudes by a predetermined amount.

With such an engagement projection 55, usually,
Since only a part of the resin coating portion 54 that covers the outer peripheral surface 59 of the shaft 5 needs to be thick, the engagement protrusion 55 can be easily formed, and the manufacturing cost for forming the engagement protrusion 55 can be reduced. It can be cheap. In the case where the engagement protrusion 55 including the thick portion 58 is used, a conventional shaft can be used as an intermediate product of the shaft 5 before the engagement protrusion 55 is formed. That is, the resin coating portion 54 may be formed on the conventional shaft so that a part thereof becomes the thick portion 58.

The engaging projection 55 is provided only on a part in the circumferential direction. The position of the engaging projection 55 in the circumferential direction is preferably a position avoiding the tooth surface 62 of the cylinder 4, for example, a plurality of concave peripheral surfaces 53 of the shaft 5 and a distal end surface 60 of the ridge 51. When provided at such a position, there is an advantage that the intermediate shaft 1 can be extended and contracted without the tooth surface 62 of the cylinder 4 being in contact with the engagement projection 55 in a state where the engagement projection 55 is located inside the cylinder 4. is there. Therefore, without forcing the tooth surface 62 of the cylinder 4,
Alternatively, the engagement force can be obtained by increasing the amount of protrusion of the engagement protrusion 55 without increasing the circumferential play between the shaft 5 and the cylinder 4.

In order to form the engagement protrusion 55 only on a part of the circumferential direction, the resin coating portion 54 is formed to be thick over the entire circumference of the shaft 5, and then the resin coating portion 54 corresponding to the tooth surface 62 is formed. By removing the surface of the portion so as to be thin, only the portion of the resin covering portion 54 corresponding to the plurality of hollow peripheral surfaces 53 and the tip end surface 60 of the ridge 51 is left thick. Is also good. As described above, according to the present invention, the engagement protrusion 55 of the shaft 5 that engages with the seal member 6 only when incorporated into the vehicle prevents the shaft 5 and the cylinder 4 from coming off due to its own weight, and does not support it by hand. Therefore, the intermediate shaft 1 can be easily installed because the posture suitable for installation can be maintained autonomously. In addition, since the intermediate shaft 1 can be smoothly expanded and contracted in the state in which the engagement is released, there is no problem in the normal operation after the assembly.

The engaging projection 55 may be provided not only in a part of the circumferential direction but also over the entire circumference. In this case, the engaging force can be obtained over the entire circumference. Further, the plurality of engagement protrusions 55 may be arranged in the axial direction. In addition, various design changes can be made without changing the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic view of an intermediate shaft of a steering device according to an embodiment of the present invention, and shows a state when assembled to a vehicle body.

FIG. 2 is a front view of the intermediate shaft shown in FIG.

3 is a sectional side view of a main part of the intermediate shaft shown in FIG. 2,
3 shows an AA cross section of FIG. 2.

FIG. 4 is a sectional front view of a portion B shown in FIG. 2, and FIG.
2 shows a C-section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intermediate shaft 4 Tube 5 Shaft 6 Seal member 31 Inner peripheral edge of seal member 41 End of tube 43 Inner of tube 54 Resin coating portion 55 Engagement protrusion 56 Engagement slope 58 Thick portion (part of resin coating portion) Outer surface of shaft 59

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Kawahara 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Koyo Seiko Co., Ltd. F-term (reference) 3D030 DC40

Claims (3)

[Claims] An intermediate shaft of a steering device comprising a cylinder and a shaft which are telescopically fitted to each other, and which is subjected to a detachment load due to its own weight when incorporated into an actual machine in a substantially shortened state, wherein the shaft is provided at an end of the cylinder. And a projection provided on the shaft, which engages with the seal member only in the substantially shortest state to generate an engagement force against the detachment load. The intermediate shaft of the steering device. 2. The intermediate shaft of the steering device according to claim 1, wherein the engagement protrusion has an engagement slope on a side from which the shaft is removed, and the engagement protrusion is located in the cylinder in the substantially shortened state. An intermediate shaft of a steering device, wherein the engagement slope is engaged with an inner peripheral edge of a seal member. 3. The intermediate shaft of the steering device according to claim 1, wherein the engagement protrusion is formed by thickening a part of a resin coating portion that covers an outer peripheral surface of the shaft. An intermediate shaft of the steering device.